the corona is a midsize car around the size of a camry, right? i think 16's would be too small for it. at least 17's should be your target, and if you really are looking for porma points, go 18's...although these are more expensive and you will have to drive them more carefully.

as far as side mirror signal lights go, there are kits available for this, but i'm not sure they fit the Corona. abangan ko na lang someone with local knowledge. fyi, they will require that you replace both mirror assemblies (and paint them as well)